Computers show why Earth’s core is so dense

UC DAVIS (US) — Scientists have used computer simulations to solve a long-standing mystery: what accounts for Earth’s core density?

The simulations shows that Earth’s core contains 0.1-0.8 percent carbon, the largest reservoir of carbon on the planet. The findings by researchers at the University of California, Davis, and the Chinese Academy of Sciences in Beijing were published this week in Proceedings of the National Academy of Sciences.

“We knew the density of the core, and we knew that metal iron and nickel alone couldn’t account for that density,” says UC Davis geology professor and study co-author Qing-Zhu Yin. “You need something lighter.”


Carbon was one of the major missing light element candidates; others included silicon, oxygen, phosphorus, magnesium, hydrogen, and nitrogen.

To discover their content in the Earth’s core, Yin and co-author Yigang Zhang went to the computer.

“We played with about 260 atoms to try to simulate Earth’s formation,” Yin explains. “We assigned them their basic properties and let the quantum mechanics do the work in the computer.

“Now we know how to account for that density deficit.”

An accurate knowledge of carbon’s influence will help to increase our understanding of the Earth’s age and the exact timing of the core’s formation.

“It’s about understanding the nature of the Earth,” Yin says. “We’re able to better understand the physical and chemical processes involved in Earth’s formation.”

The Chinese Academy of Sciences funded the research.

Source: UC Davis